This disclosure relates to liquid crystal displays (LCDs), in general, and in particular, to substrates for liquid crystal display panels that reduce pixel defects in panels incorporating them.
LCD display panels include an array substrate having thin film transistors (TFTs) and pixel electrodes, a color substrate having color filters and a common electrode, and a layer of a liquid crystal material disposed between the array substrate and the color filter substrate. The array substrate further includes a plurality of gate wirings and a plurality of source wirings crossing each other and defining a plurality of unit pixels, with one of the TFTs and one of the pixel electrodes being formed in each of the unit pixels.
Each of the TFTs is electrically connected to an associated one of the pixel electrodes, and is operable to couple an electric charge onto the pixel electrode. An electric field is formed between the pixel electrode and the common electrode that controls the arrangement of the molecules of the liquid crystal material and thereby controls the amount of light transmitted through the pixel.
The electric charge coupled onto the pixel electrode maintains the electric field between the two electrodes during an image frame by means of a storage capacitor formed in the unit pixel area between an associated storage wiring and the pixel electrode. When the storage wiring is disconnected, or when the storage wiring is short-circuited with an adjacent data wiring, the storage capacitor in the unit pixel area is not formed normally, so that the unit pixel cannot control the liquid crystal material correctly, thereby causing a defective pixel.
Recently, in order to improve the side viewing angle of an LCD panel, a design has been put forward in which the pixel electrode is divided into a first sub electrode and a second sub electrode. A first pixel voltage is applied to the first sub electrode, and a second pixel voltage, which is larger than the first pixel voltage, is applied to the second sub electrode. As a result, the directions in which the molecules of the liquid crystal layer in the unit pixel area are more diverse, so that the side viewing angle of the LCD panel is desirably improved.
However, when the pixel electrode is divided into first and sub electrodes, the number of defects of the associated storage capacitor for maintaining the first pixel voltage and the second pixel voltage using only one storage wiring is increased.